{
  "spore": "profile",
  "id": "constantan",
  "spore_version": "0.2",
  "family": "resistance-and-thermocouple-alloys",
  "name": "Constantan",
  "abbreviation": "CuNi",
  "role": "precision resistance alloy and thermocouple leg",
  "category": "metals",
  "type": "copper-alloys",
  "summary": "Constantan is a copper-nickel alloy of about 55 % copper and 45 % nickel, sold as DIN 2.0842, UNS C72150 and CuNi44Mn1. Its electrical resistance stays nearly constant over a wide temperature range, which is why it is used in strain gauges, precision and shunt resistors, and as one leg of thermocouples. Matthey gives a density of 8.9 g/cm3, a thermal conductivity of 21.2 W/(m·K) at 20 °C and a temperature coefficient of resistance of -80 to +40 ppm/K. Soft annealed strip has a tensile strength of 360 to 460 MPa and at least 25 % elongation, and the maker rates the alloy to 600 °C.\n",
  "best_for": "Precision resistors, strain gauges and thermocouple legs that need a resistance which stays nearly constant with temperature, up to about 600 °C",
  "weakest_at": "Conduction and heat flow: resistivity of 52 µΩ·cm (Goodfellow) and thermal conductivity of 21.2 W/(m·K) (Matthey) make it a resistor alloy, not a conductor. Nickel content also brings a skin-sensitisation hazard (H317 on the nickel SDS).",
  "identity": {
    "formula": "Cu-Ni alloy, nominal 55 % Cu and 45 % Ni, with 0.50 to 2.00 % Mn (Matthey CuNi44Mn1); Cu balance, Ni 43 to 45 %, Mn 0.7 to 1.3 %, Fe up to 1 % (BGH CuniTHERM 44)",
    "designations": [
      {
        "system": "UNS",
        "code": "C72150",
        "source": "bgh-cunitherm44",
        "where": "Material Designation table, row C72150, label UNS"
      },
      {
        "system": "EN",
        "code": "2.0842",
        "source": "bgh-cunitherm44",
        "where": "Material Designation table, row 2.0842, label DIN; Standards line DIN 17471"
      },
      {
        "system": "EN name",
        "code": "CuNi44Mn1",
        "source": "matthey-cunimn44",
        "where": "Title block, designation CuNi44Mn1"
      },
      {
        "system": "Trade name",
        "code": "Constantan",
        "source": "bgh-cunitherm44",
        "where": "Properties paragraph: also known under the brand name constantan"
      }
    ],
    "source": "matthey-cunimn44",
    "where": "Chemical composition table, row Cu Balance, Ni 43.0 - 45.0, Mn 0.50 - 2.00 (weight %). The BGH sheet prints the same nominal split: Ni min 43 and max 45, Cu balance."
  },
  "tags": {
    "environments": [],
    "stresses": [],
    "applications": [
      "electronics-and-chips",
      "thermal-control",
      "structures"
    ]
  },
  "properties": [
    {
      "benchmark": "density",
      "label": "Density, CuNi44Mn1 strip",
      "value": 8.9,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temperature": "not stated"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Physical properties table, row Density",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "density",
      "label": "Density, annealed wire 0.15 mm",
      "value": 8.9,
      "bound": "exact",
      "unit": "g/cm3",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire, diameter 0.15 mm (Goodfellow SKU 1000058743)",
        "temperature": "not stated"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Physical Properties table, row Density",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point range, CuNi44Mn1",
      "value": 1230,
      "value_high": 1290,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "pressure": "not stated"
      },
      "method": "Range printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Physical properties table, row Melting point",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "melting_point",
      "label": "Melting point range, annealed wire",
      "value": 1225,
      "value_high": 1300,
      "bound": "range",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire 0.15 mm (Goodfellow)",
        "pressure": "not stated"
      },
      "method": "Range printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Thermal Properties table, row Melting point",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "electrical_resistivity",
      "label": "Electrical resistivity, annealed wire 0.15 mm",
      "value": 52,
      "bound": "exact",
      "unit": "µΩ·cm",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire 0.15 mm (Goodfellow SKU 1000058743)",
        "temperature": "not stated"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Electrical Properties table, row Electrical resistivity",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 20 °C, CuNi44Mn1 strip",
      "value": 21.2,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temperature": "20 °C"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Physical properties table, row Thermal conductivity at 20°C",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermal_conductivity",
      "label": "Thermal conductivity at 23 °C, annealed wire",
      "value": 19.5,
      "bound": "exact",
      "unit": "W/(m·K)",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire 0.15 mm (Goodfellow)",
        "temperature": "23 °C"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Thermal Properties table, row Thermal conductivity",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, 20 to 300 °C, CuNi44Mn1 strip",
      "value": 14.5,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temperature": "20 to 300 °C"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Physical properties table, row Linear dilatation coefficient (20-300 ºC)",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "cte",
      "label": "Coefficient of thermal expansion, 20 to 100 °C, annealed wire",
      "value": 14.9,
      "bound": "exact",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire 0.15 mm (Goodfellow)",
        "temperature": "20 to 100 °C"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Thermal Properties table, row Coefficient of thermal expansion",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "specific_heat",
      "label": "Specific heat capacity at 20 °C, CuNi44Mn1 strip",
      "value": 0.41,
      "bound": "exact",
      "unit": "kJ/(kg·K)",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temperature": "20 °C"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Physical properties table, row Thermal capacity (Cp) at 20ºC",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity, CuNi44Mn1 strip",
      "value": 165,
      "bound": "exact",
      "unit": "kN/mm2",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temperature": "not stated"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Physical properties table, row Modulus of elasticity",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elastic_modulus",
      "label": "Modulus of elasticity, annealed wire 0.15 mm",
      "value": 162,
      "bound": "exact",
      "unit": "GPa",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire 0.15 mm (Goodfellow)",
        "temperature": "not stated"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Mechanical Properties table, row Modulus of elasticity",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, soft annealed strip (R360, H90)",
      "value": 360,
      "value_high": 460,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temper": "soft annealed, R360 / H90",
        "product_form": "strip"
      },
      "method": "Range printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Mechanical properties of strips, row R360 H90 soft annealed, column Rm (N/mm2)",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, half-hard strip (R500, H150)",
      "value": 500,
      "value_high": 700,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temper": "1/2 hard, R500 / H150",
        "product_form": "strip"
      },
      "method": "Range printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Mechanical properties of strips, row R500 H150 1/2 hard, column Rm (N/mm2)",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, hard strip (R740, H230), minimum",
      "value": 740,
      "bound": "lower",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temper": "hard, R740 / H230",
        "product_form": "strip"
      },
      "method": "Minimum value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Mechanical properties of strips, row R740 H230 hard, column Rm (N/mm2)",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "ultimate_tensile_strength",
      "label": "Tensile strength, annealed wire 0.15 mm",
      "value": 400,
      "value_high": 590,
      "bound": "range",
      "unit": "MPa",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire 0.15 mm (Goodfellow)",
        "temper": "annealed"
      },
      "method": "Range printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Mechanical Properties table, row Tensile strength",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation, soft annealed strip (R360, H90)",
      "value": 25,
      "bound": "lower",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temper": "soft annealed, R360 / H90",
        "gauge_length": "A50mm"
      },
      "method": "Minimum value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Mechanical properties of strips, row R360 H90 soft annealed, column A50mm (%)",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "elongation",
      "label": "Elongation at break, annealed wire 0.15 mm",
      "value": 45,
      "bound": "exact",
      "unit": "%",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire 0.15 mm (Goodfellow)",
        "temper": "annealed"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Mechanical Properties table, row Elongation at break",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum application temperature, CuNi44Mn1",
      "value": 600,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "basis": "maximum application temperature, as stated by the maker"
      },
      "method": "Value printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Main technical properties and features, last sentence; also Physical properties table, row Maximum application temperature",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "max_service_temp",
      "label": "Maximum use temperature in air, annealed wire",
      "value": 500,
      "bound": "exact",
      "unit": "°C",
      "scope": "material",
      "conditions": {
        "form": "annealed spooled wire 0.15 mm (Goodfellow)",
        "atmosphere": "air"
      },
      "method": "Value printed in a supplier product page",
      "status": "ground",
      "source": "goodfellow-wire",
      "where": "Thermal Properties table, row Maximum use temperature in air",
      "source_detail": {
        "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
        "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
        "kind": "datasheet",
        "license": "Supplier product page (cited, not reproduced)"
      }
    },
    {
      "benchmark": "temperature_coefficient_of_resistance",
      "label": "Temperature coefficient of electrical resistance, CuNi44Mn1",
      "value": -80,
      "value_high": 40,
      "bound": "range",
      "unit": "ppm/K",
      "scope": "material",
      "conditions": {
        "grade": "CuNi44Mn1 (Matthey)",
        "temperature": "20 to 105 °C"
      },
      "method": "Range printed in a manufacturer datasheet",
      "status": "ground",
      "source": "matthey-cunimn44",
      "where": "Physical properties table, row Temperature coefficient of electrical resistance (20-105 °C)",
      "source_detail": {
        "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
        "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
        "year": 2022,
        "kind": "datasheet",
        "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
      }
    },
    {
      "benchmark": "thermoelectric_emf_vs_copper",
      "label": "Thermoelectric emf compared with copper",
      "value": -40,
      "bound": "exact",
      "unit": "µV/K",
      "scope": "material",
      "conditions": {
        "reference": "emf compared with copper (Cu)",
        "temperature": "not stated in the printed table"
      },
      "method": "Value printed in a manufacturer datasheet (DIN 17471 physical properties)",
      "status": "ground",
      "source": "bgh-cunitherm44",
      "where": "Physical Properties table acc. to DIN 17471, row Thermoelectric emf compared to Cu",
      "source_detail": {
        "title": "BGH CuniTHERM 44, premium resistance alloy datasheet (Rev. 1, English)",
        "url": "https://bgh.de/media/84/0c/4d/1775720815/BGH_CuniTHERM%2044_en.pdf",
        "kind": "datasheet",
        "license": "Manufacturer datasheet, unbinding first orientation (cited, not reproduced)"
      }
    }
  ],
  "corrosion": [
    {
      "environment": "Oxygen-containing and oxidising sulphurous gases at high temperature",
      "headline": "The alloy is scale-resistant and resists oxidising sulphurous gases up to 600 °C.",
      "effect": "BGH says the material is scale-resistant and resistant up to 600 °C to oxygen-containing and oxidising sulphurous gases, and to carburisation, among others. The sheet gives no test data or rate.",
      "rating": "low",
      "conditions": {
        "temperature": "up to 600 °C",
        "basis": "manufacturer statement, no test data printed"
      },
      "source": "bgh-cunitherm44",
      "where": "Description paragraph under Properties"
    },
    {
      "environment": "General corrosive media at ambient temperature",
      "headline": "Good corrosion resistance, malleability and ductility, and an adherent oxide coating can be applied to strip.",
      "effect": "Matthey says CuNi44Mn1 has good corrosion resistance, good malleability and ductility, and that an adherent oxide coating with excellent electrical insulation can be applied to the strip surface. No corrosion rate or immersion test is printed.",
      "rating": "low",
      "conditions": {
        "basis": "manufacturer statement, no test data printed"
      },
      "source": "matthey-cunimn44",
      "where": "Main technical properties and features"
    }
  ],
  "risks": {
    "hazards": [
      {
        "text": "Nickel is about 45 % of the alloy. The nickel wire safety data sheet (NextSDS, CAS 7440-02-0, EC 231-111-4) lists H317 May cause an allergic skin reaction, H351 Suspected of causing cancer and H372 Causes damage to the lung, the kidneys and the liver through prolonged or repeated exposure, with signal word danger. That is the nickel metal classification, not a constantan SDS, and the constantan SDS was not opened.",
        "ghs": [
          "H317",
          "H351",
          "H372"
        ],
        "source": "nextsds-ni",
        "where": "Hazard Classifications and Hazard Statements section of the nickel wire SDS page"
      },
      {
        "text": "Goodfellow's product page for constantan wire (0.15 mm) shows a health hazard label reading Serious health hazard. The constantan SDS is a UK document behind a download link and was not opened, so no H-codes for the alloy itself are recorded.",
        "ghs": [],
        "source": "goodfellow-wire",
        "where": "Product details block, label Health hazard"
      }
    ],
    "failure_risks": [
      {
        "mode": "Use above the maximum application temperature",
        "trigger": "Operation above 600 °C (Matthey maximum application temperature) or above 500 °C in air for annealed wire (Goodfellow)",
        "consequence": "Neither supplier prints property data above these limits, so the alloy is outside its rated range. The sources give no failure data for that case.",
        "severity": "moderate",
        "source": "matthey-cunimn44",
        "where": "Main technical properties and features (maximum application temperature 600 °C); Goodfellow product page for the 500 °C air limit"
      },
      {
        "mode": "Wrong temper for the load",
        "trigger": "Soft annealed strip specified where hard strip is meant, or the reverse",
        "consequence": "Minimum tensile strength falls from 740 MPa in the hard temper to 360 to 460 MPa when soft annealed, so the temper sets the strength of the part.",
        "severity": "low",
        "source": "matthey-cunimn44",
        "where": "Mechanical properties of strips, rows R360 H90, R500 H150 and R740 H230"
      }
    ],
    "side_effects": [
      {
        "text": "The alloy is about 45 % nickel, so its cost follows nickel supply and price. The USGS says the 2025 average LME nickel cash price fell by an estimated 11 % from 2024, and that the global primary nickel market has been in surplus since 2022.",
        "affects": "Cost of the alloy",
        "source": "usgs-ni-2026",
        "where": "Events, Trends, and Issues section"
      }
    ],
    "handling": [
      {
        "text": "Specify the temper when ordering. Soft annealed strip has 360 to 460 MPa tensile strength and hard strip 740 MPa minimum (Matthey), and the Goodfellow wire is supplied annealed.",
        "source": "matthey-cunimn44",
        "where": "Mechanical properties of strips table"
      },
      {
        "text": "The nickel wire SDS lists skin sensitisation (H317) for the nickel component, so the constantan SDS from the supplier should be checked before handling the wire.",
        "source": "nextsds-ni",
        "where": "Hazard Statements section"
      }
    ],
    "mitigations": []
  },
  "uses": [
    {
      "application": "electronics-and-chips",
      "device": "Precision and shunt resistors, and measuring resistors",
      "example": "Matthey lists shunt resistors for ammeters and electrical resistors for measurement among typical uses. BGH lists precision and measuring resistors. Its near-constant resistivity is the reason for the choice.",
      "source": "matthey-cunimn44",
      "where": "Typical uses section; also BGH Typical Applications list"
    },
    {
      "application": "thermal-control",
      "device": "Thermocouple leg (copper-nickel or iron pairing) for temperature measurement",
      "example": "Matthey says the very high EMF of CuNi44Mn1 suits thermocouples combined with other metals. BGH gives a thermoelectric emf of -40 µV/K against copper. The NIST-based Type T table pairs copper with copper-nickel over -200 to 350 °C in its thermocouple grade.",
      "source": "mst-typet",
      "where": "Type T reference table, title block (Copper vs. Copper-Nickel; maximum temperature range, thermocouple grade); Matthey Main technical properties"
    },
    {
      "application": "structures",
      "device": "Strain gauge grids and multipurpose instrumentation cable",
      "example": "Matthey and Goodfellow both list strain gauges as a use. AEC-NASA Tech Brief 67-10046 (1967, Space Nuclear Propulsion Office) describes a cable with a constantan conductor that forms the negative leg of a copper/constantan thermocouple, so a strain gauge's own temperature can be measured. This is a development record, not a flight record.",
      "source": "ntrs-1967",
      "where": "Brief 67-10046, The problem and How it's done sections; Matthey Typical uses"
    },
    {
      "application": "thermal-control",
      "device": "Heating wires, cables and heating mats up to 600 °C",
      "example": "BGH lists heating wires and cables and heating mats, for low-temperature heating elements with application temperatures up to 600 °C.",
      "source": "bgh-cunitherm44",
      "where": "Application Area and Typical Applications, Physical Properties paragraph"
    }
  ],
  "supply": [
    {
      "subject": "Copper (about 55 % of the alloy), mine production 2025e",
      "producers": [
        {
          "country": "Chile",
          "share_percent": 23,
          "year": 2025
        },
        {
          "country": "Congo (Kinshasa)",
          "share_percent": 13.9,
          "year": 2025
        },
        {
          "country": "Peru",
          "share_percent": 11.7,
          "year": 2025
        },
        {
          "country": "China",
          "share_percent": 7.8,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 5.7,
          "year": 2025
        }
      ],
      "critical_lists": [
        {
          "list": "U.S. Final 2025 List of Critical Minerals (copper added, per the USGS Mineral Commodity Summaries 2026)",
          "listed": true
        }
      ],
      "recycling": "USGS: old scrap provided about 30 % of the U.S. copper supply in 2025, and brass and wire-rod mills took about 80 % of the copper recovered from scrap.",
      "substitutes": [
        "USGS: aluminium substitutes for copper in electrical equipment and power cable."
      ],
      "source": "usgs-cu-2026",
      "where": "World Mine and Refinery Production table, mine production 2025e (world total 23,000 thousand t). Shares calculated from the printed country values 5,300, 3,200, 2,700, 1,800 and 1,300 over 23,000. Critical list in the 2025 list paragraph. Recycling and Substitutes sections."
    },
    {
      "subject": "Nickel (about 45 % of the alloy), mine production 2025e",
      "producers": [
        {
          "country": "Indonesia",
          "share_percent": 66.7,
          "year": 2025
        },
        {
          "country": "Philippines",
          "share_percent": 6.9,
          "year": 2025
        },
        {
          "country": "Russia",
          "share_percent": 5.1,
          "year": 2025
        },
        {
          "country": "Canada",
          "share_percent": 3.6,
          "year": 2025
        },
        {
          "country": "New Caledonia",
          "share_percent": 3.6,
          "year": 2025
        }
      ],
      "critical_lists": [],
      "recycling": "USGS: nickel recovered from scrap accounted for about 60 % of U.S. apparent consumption in 2025. The last U.S. primary nickel refinery stopped operating in 1985.",
      "substitutes": [
        "USGS: titanium alloys can substitute for nickel or nickel-base alloys in corrosive environments; low-nickel and duplex stainless steels substitute for austenitic grades."
      ],
      "source": "usgs-ni-2026",
      "where": "World Mine Production and Reserves table, 2025e column (world total 3,900,000 t). Shares calculated from the printed values 2,600,000, 270,000, 200,000 and 140,000 (twice) over 3,900,000. Recycling and Substitutes paragraphs."
    }
  ],
  "media": [],
  "documents": [
    {
      "title": "BGH CuniTHERM 44 (constantan) premium resistance alloy datasheet, Rev. 1",
      "type": "datasheet",
      "url": "https://bgh.de/media/84/0c/4d/1775720815/BGH_CuniTHERM%2044_en.pdf"
    },
    {
      "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E)",
      "type": "datasheet",
      "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
      "year": 2022
    },
    {
      "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product and properties page",
      "type": "datasheet",
      "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743"
    },
    {
      "title": "Goodfellow, Constantan resistance alloy wire, material information",
      "type": "report",
      "url": "https://www.goodfellow.com/usa/resources/constantan-resistance-alloy-wire-material-information/",
      "year": 2024
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Copper",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf",
      "year": 2026
    },
    {
      "title": "USGS Mineral Commodity Summaries 2026: Nickel",
      "type": "report",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf",
      "year": 2026
    },
    {
      "title": "NIST Monograph 175 revised to ITS-90, Thermocouple Reference Tables, Type T (copy hosted by Missouri S&T)",
      "type": "database",
      "url": "https://web.mst.edu/cottrell/ME240/Resources/Temperature/Type%20T%20TC%20Table.pdf"
    },
    {
      "title": "NextSDS, Nickel wire safety data sheet, CAS 7440-02-0, hazard classification",
      "type": "sds",
      "url": "https://nextsds.com/sds/en/281331501257788/nickel-wire"
    },
    {
      "title": "AEC-NASA Tech Brief 67-10046, Multipurpose Instrumentation Cable Provides Integral Thermocouple Circuit (March 1967)",
      "type": "report",
      "url": "https://ntrs.nasa.gov/api/citations/19670000046/downloads/19670000046.pdf",
      "year": 1967
    }
  ],
  "gaps": [
    "Electrical resistivity 0.49 Ω mm²/m at 20 °C from the BGH sheet is not entered: the sheet prints it with a decimal comma (0,49), which the value check cannot match. The Goodfellow value of 52 µΩ·cm is entered instead.",
    "Matthey prints electrical resistivity as 49 with the unit cm (the micro sign is lost in the PDF text), so the unit is not confirmed and the value is not entered. Goodfellow's material information page gives 49 × 10⁻⁸ Ω·m at 20 °C in a form the unit parser cannot take, so it is not entered either.",
    "The BGH sheet prints its melting temperature (1280), thermal expansion (13.5 and 15) and temperature-coefficient range under a column header in °F. Those values are not entered because the unit is not confirmed. The BGH sheet's decimal-comma density (8,9), specific heat (0,41) and thermal conductivity (23,0) are also not entered, for the same comma reason as the resistivity.",
    "Yield strength: no source read in this run gives a yield value for constantan, so only tensile strength and elongation are entered.",
    "Hardness: Goodfellow gives 100 to 300 HB (Brinell) and Matthey gives 90 to 135 HV (soft) and 150 to 220 HV (half hard). Neither is entered because no canonical hardness name exists in the property list.",
    "Temperature coefficient of resistance and thermoelectric emf are entered under names that are not in the canonical property list (temperature_coefficient_of_resistance, thermoelectric_emf_vs_copper). They need adding to the list.",
    "Designations: BGH also prints UNS N04401 for the same product; it is not entered because it is a different UNS number from C72150 and the sheet does not call the two the same grade. Wikipedia gives the trade names Eureka, Advance and Ferry; it was not used for designations, because the brief limits Wikipedia to composition and history.",
    "Constantan SDS: the supplier SDS (Goodfellow, UK) was not opened, so no H-codes for the alloy are recorded. The hazard entries use the nickel metal SDS and the supplier's health hazard label.",
    "Spacecraft, rocket and satellite use: no flight record of constantan was found in a source read in this run. The 1967 AEC-NASA Tech Brief describes a Space Nuclear Propulsion Office instrumentation cable, which is a development record. A 1977 NASA surface-thermocouple brief was seen in a search result only and not opened.",
    "Type J (iron-constantan): the pairing is not confirmed from a source read in this run. The ISA MC96.1 preview and the Omega table were not readable in this run.",
    "Vacuum and space environment: no outgassing, atomic-oxygen, radiation or cold-welding data for constantan was found.",
    "Supply shares are calculated from printed USGS values, not printed as percentages in the sources.",
    "Fatigue, creep and drift: BGH and Matthey give no drift or fatigue data. Wikipedia reports drift above 65 °C in strain gauge use, but it was not used for property or failure values under the brief."
  ],
  "story": {
    "why": "Constantan is a copper-nickel alloy of about 55 % copper and 45 % nickel. Its electrical resistance stays nearly constant over a wide temperature range, so it is used where a resistor must not drift with temperature. Matthey gives a temperature coefficient of resistance of -80 to +40 ppm/K over 20 to 105 °C. The same alloy has a thermoelectric emf against copper of -40 µV/K, so it is also used as one leg of a thermocouple. It is a strain gauge alloy too, with 162 GPa modulus and 45 % elongation in annealed wire.",
    "uses": [
      {
        "where": "Resistors and gauges",
        "line": "Matthey lists shunt resistors for ammeters, measuring resistors and strain gauges among its typical uses. BGH lists precision and measuring resistors. Goodfellow describes the wire as used in strain gauges, resistance thermometers and precision shunt resistors."
      },
      {
        "where": "Thermocouples",
        "line": "Matthey says the alloy's very high emf suits thermocouples combined with other metals. A NIST-based Type T table pairs copper with copper-nickel over -200 to 350 °C in its thermocouple grade."
      },
      {
        "where": "Heating elements",
        "line": "BGH lists heating wires and cables and heating mats, for low-temperature heating elements with application temperatures up to 600 °C."
      },
      {
        "where": "Aerospace instrumentation",
        "line": "A 1967 AEC-NASA Tech Brief describes a multipurpose cable with a constantan conductor that doubles as a thermocouple leg, so a strain gauge's temperature can be measured without a second thermocouple. It is a development record, not a flight record."
      }
    ],
    "can_do": [
      {
        "label": "Stay constant",
        "line": "Matthey gives a temperature coefficient of electrical resistance of -80 to +40 ppm/K over 20 to 105 °C.",
        "benchmark": "temperature_coefficient_of_resistance",
        "scope": "material",
        "value": "-80 to +40 ppm/K"
      },
      {
        "label": "Carry heat",
        "line": "Matthey gives a thermal conductivity of 21.2 W/(m·K) at 20 °C. Goodfellow gives 19.5 W/(m·K) at 23 °C for annealed wire.",
        "benchmark": "thermal_conductivity",
        "scope": "material",
        "value": "21.2 W/(m·K)"
      },
      {
        "label": "Stay in the heat",
        "line": "Matthey gives 600 °C as the maximum application temperature. BGH says the alloy is scale-resistant up to 600 °C in oxidising sulphurous gases.",
        "benchmark": "max_service_temp",
        "scope": "material",
        "value": "600 °C"
      },
      {
        "label": "Weight",
        "line": "Density is 8.9 g/cm3 in both the Matthey strip sheet and the Goodfellow wire page.",
        "benchmark": "density",
        "scope": "material",
        "value": "8.9 g/cm3"
      },
      {
        "label": "Strength by temper",
        "line": "Tensile strength is 360 to 460 MPa in soft annealed strip, 500 to 700 MPa in half-hard strip and at least 740 MPa in hard strip (Matthey).",
        "benchmark": "ultimate_tensile_strength",
        "scope": "material",
        "value": "360 to 740 MPa"
      }
    ],
    "compare": "Two suppliers give different thermal conductivities for the same nominal alloy: 21.2 W/(m·K) at 20 °C from Matthey and 19.5 W/(m·K) at 23 °C from Goodfellow for annealed wire. Matthey's strip tempers span tensile strengths from 360 to 740 MPa, so the temper decides the strength. The table rows are examples from these two datasheets, not a ranking.",
    "compare_rows": [
      {
        "label": "Density",
        "benchmark": "density",
        "scope": "material"
      },
      {
        "label": "Thermal conductivity",
        "benchmark": "thermal_conductivity",
        "scope": "material"
      },
      {
        "label": "Maximum temperature",
        "benchmark": "max_service_temp",
        "scope": "material"
      }
    ],
    "handling": [
      "Name the temper on the order, because strength runs from 360 to 460 MPa soft to 740 MPa minimum hard.",
      "Keep the alloy at or below 600 °C in use, the maximum application temperature given by Matthey.",
      "Read the supplier SDS before handling, since the nickel component carries H317, H351 and H372 in its own SDS."
    ],
    "good_for": [
      "Precision resistance with a temperature coefficient of -80 to +40 ppm/K (Matthey).",
      "Strain gauges and thermocouple legs, with a 162 GPa modulus and 45 % elongation in annealed wire (Goodfellow).",
      "Use up to 600 °C in oxidising gases, as stated by BGH and Matthey."
    ],
    "watch_out": [
      "Nickel content: the nickel component is classified H317, H351 and H372 in its own SDS.",
      "Conduction: resistivity is 52 µΩ·cm (Goodfellow), so the alloy is a resistor, not a conductor.",
      "Temper: strength depends strongly on temper, from 360 to 460 MPa soft to 740 MPa minimum hard.",
      "Supply: about 67 % of 2025 world nickel mine output came from Indonesia (USGS).",
      "Space: no flight record of constantan was found in the sources read; the 1967 NASA brief is a development record."
    ],
    "verdict": "Constantan is a copper-nickel resistance alloy whose resistance barely changes with temperature, with -80 to +40 ppm/K from Matthey. It also works as a thermocouple leg and a strain gauge alloy, rated to 600 °C. Its nickel content carries a hazard classification, the datasheets give no failure data above the rated limits, and no flight record in a space source was found.",
    "recipe": {
      "line": "Constantan is a copper-nickel alloy (Cu-Ni) with a face-centred cubic crystal structure, typically 55 % copper and 45 % nickel (Goodfellow material information). Matthey's CuNi44Mn1 adds 0.50 to 2.00 % manganese and up to 0.50 % iron (Matthey composition table). It is supplied as wire, strip and foil.",
      "parts": [
        {
          "name": "Copper",
          "symbol": "Cu",
          "role": "Base metal of the alloy. Copper sets the low-cost matrix that the nickel is dissolved in."
        },
        {
          "name": "Nickel",
          "symbol": "Ni",
          "role": "Main alloying element. It gives the alloy its near-constant resistivity with temperature."
        },
        {
          "name": "Manganese",
          "symbol": "Mn",
          "role": "Minor addition in the CuNi44Mn1 grade."
        }
      ]
    },
    "risk_groups": [
      {
        "title": "For people",
        "lead": "The hazard of constantan comes from its nickel. The opened sources classify nickel metal, not the alloy itself, and the supplier's own SDS was not read.",
        "points": [
          {
            "label": "Nickel in the alloy",
            "line": "The nickel wire SDS lists H317 (allergic skin reaction), H351 (suspected of causing cancer) and H372 (damage to lungs, kidneys and liver through prolonged exposure). Nickel is about 45 % of constantan."
          },
          {
            "label": "Supplier label",
            "line": "Goodfellow's constantan wire page shows a health hazard label reading Serious health hazard. The full SDS was not opened."
          }
        ],
        "level": 1,
        "verdict": "Nickel classification"
      },
      {
        "title": "If it fails",
        "lead": "The sources give rating and temper limits, but no failure data for the alloy beyond them.",
        "points": [
          {
            "label": "Above 600 °C",
            "line": "Matthey gives 600 °C as the maximum application temperature, and Goodfellow gives 500 °C in air for annealed wire. Above those limits no property data are printed."
          },
          {
            "label": "Wrong temper",
            "line": "Hard strip has at least 740 MPa tensile strength, against 360 to 460 MPa when soft annealed."
          }
        ]
      },
      {
        "title": "Handling and storage",
        "points": [
          {
            "label": "Choose the temper",
            "line": "Name the temper on the order. Matthey gives soft (H90), half-hard (H150) and hard (H230) strip with different strengths."
          },
          {
            "label": "Check the SDS",
            "line": "Read the supplier's SDS before handling, since the nickel component carries a skin-sensitisation classification."
          }
        ]
      }
    ]
  },
  "updated": "2026-10-26",
  "review": {
    "status": "draft",
    "method": "assistant",
    "checked_values": 23,
    "unreachable": 2,
    "caveats": 6,
    "note": "Values were read by an AI assistant on 2026-10-26 from the datasheets and product page named in each entry (PDFs extracted to text). Unreachable or unconfirmed: the constantan SDS from the supplier, and the Omega and ISA Type J pages. Caveats: the BGH sheet uses a [°F] column header with values that look like °C, so those rows are left out; the Goodfellow wire values are for one 0.15 mm annealed product; Matthey strip tempers differ from wire; the nickel hazard classification is for the nickel metal, not the alloy; the space use is a 1967 development brief."
  },
  "sources": {
    "bgh-cunitherm44": {
      "title": "BGH CuniTHERM 44, premium resistance alloy datasheet (Rev. 1, English)",
      "url": "https://bgh.de/media/84/0c/4d/1775720815/BGH_CuniTHERM%2044_en.pdf",
      "kind": "datasheet",
      "license": "Manufacturer datasheet, unbinding first orientation (cited, not reproduced)"
    },
    "matthey-cunimn44": {
      "title": "Lamineries Matthey, Constantan CuNi44Mn1 technical datasheet (v22E, 2022)",
      "url": "https://www.matthey.ch/fileadmin/user_upload/downloads/fichetechnique/EN/CuNi44Mn1_v22E.pdf",
      "year": 2022,
      "kind": "datasheet",
      "license": "Manufacturer datasheet, informative only (cited, not reproduced)"
    },
    "goodfellow-wire": {
      "title": "Goodfellow, Constantan spooled wire 0.15 mm (SKU 1000058743), product page with material properties",
      "url": "https://www.goodfellow.com/uk/constantan-spooled-wire-1000058743",
      "kind": "datasheet",
      "license": "Supplier product page (cited, not reproduced)"
    },
    "goodfellow-info": {
      "title": "Goodfellow, Constantan resistance alloy wire, material information (January 2024)",
      "url": "https://www.goodfellow.com/usa/resources/constantan-resistance-alloy-wire-material-information/",
      "year": 2024,
      "kind": "web",
      "license": "Supplier web page (cited, not reproduced)"
    },
    "usgs-cu-2026": {
      "title": "Mineral Commodity Summaries 2026, Copper",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-copper.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "usgs-ni-2026": {
      "title": "Mineral Commodity Summaries 2026, Nickel",
      "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf",
      "year": 2026,
      "kind": "report",
      "license": "public domain (USGS)"
    },
    "mst-typet": {
      "title": "NIST Monograph 175 revised to ITS-90, Thermocouple Reference Tables, Type T (copy hosted by Missouri S&T)",
      "url": "https://web.mst.edu/cottrell/ME240/Resources/Temperature/Type%20T%20TC%20Table.pdf",
      "kind": "database",
      "license": "US government reference table (cited, not reproduced)"
    },
    "nextsds-ni": {
      "title": "NextSDS, Nickel wire safety data sheet, CAS 7440-02-0, hazard classification",
      "url": "https://nextsds.com/sds/en/281331501257788/nickel-wire",
      "kind": "datasheet",
      "license": "SDS summary page (cited, not reproduced)"
    },
    "ntrs-1967": {
      "title": "AEC-NASA Tech Brief 67-10046, Multipurpose Instrumentation Cable Provides Integral Thermocouple Circuit (March 1967)",
      "url": "https://ntrs.nasa.gov/api/citations/19670000046/downloads/19670000046.pdf",
      "year": 1967,
      "kind": "report",
      "license": "public domain (NASA)"
    }
  },
  "license": "CC-BY-4.0",
  "url": "https://spacemushroom.com/profiles/constantan/"
}